:root {
    font-size: 15px;
    user-select: none;
    -webkit-user-select: none;
}

body {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #0d7073;
}

.prompt {
    position: absolute;
    width: 300px;
    height: 142px;
    background-color: #bfbfbf;
    padding: 1px;
}

.title {
    background-color: #00007f;
    color: #fff;
    padding: 3px 20px;
    cursor: move;
    box-sizing: border-box;
    width: calc(100% - 2px);
}

.prompt::before,
.prompt::after {
    content: '';
    position: absolute;
    display: block;
    width: inherit;
    height: inherit;
    border: 2px solid;
    border-color: #dfdfdf #000 #000 #dfdfdf;
    left: -2px;
    top: -2px;
    pointer-events: none;
}

.prompt::after {
    border: 1px solid #fff;
    border-color: #fff #7f7f7f #7f7f7f #fff;
    left: -1px;
    top: -1px;
}

.message {
    margin-top: 15px;
    height: 100px;
    text-align: center;
    display: flex;
    flex-direction: column;
    justify-content: space-around;
    align-items: center;
}

button {
    position: relative;
    width: 120px;
    height: 24px;
    background-color: #bfbfbf;
    border: 0;
    padding: 0;
    margin: 0;
    font-size: 14px;
    pointer-events: none;
}

button::before,
button::after {
    content: '';
    position: absolute;
    display: block;
    width: inherit;
    height: inherit;
    border: 2px solid;
    border-color: #dfdfdf #000 #000 #dfdfdf;
    left: -2px;
    top: -2px;
    pointer-events: none;
}

button::after {
    border: 1px solid #fff;
    border-color: #fff #7f7f7f #7f7f7f #fff;
    left: -1px;
    top: -1px;
}